The present invention relates to a copying machine with an automatic document feeder.
With conventional copying machines of this type, the copying machine main body and the automatic document feeder may be separately driven by motors, or control of the copying machine main body and control of the automatic document feeder may be performed independently of each other. In such a case, due to fluctuations in the load or the power source voltage, the ratio of the convey speed of the document to the convey speed of the copy sheets may deviate vastly from the preset value, resulting in incorrect copying operation. When control for the copying machine main body and the automatic document feeder is performed independently of each other, a circuit is required to couple the control section for the copying machine main body and the control section for the automatic document feeder so that the detection of jamming of the document or the like may be performed. This results in complex control procedure.
Furthermore, when there is no relationship between the control of the copying main body and the control of the automatic document feeder, detection of jamming of the document at the automatic document feeder tends to become incorrect. When jamming is detected upon depression of the jamming detection switch at a timing which is not the timing for detection of jamming at the side of the copying machine main body, jamming may be detected due to the erroneous operation of this switch or the noise of the signal transmission system although no jamming is involved. When an automatic document feeder is used, the document is continuously inserted into this automatic document feeder. Depending upon the position of the jamming detection switch, jamming may be detected when the document is set under the normal condition during the inoperative period of the jamming detection switch.